Domestic devices get their energy in two main ways. A battery transfers energy from its chemical store, and the energy is transferred electrically to the device. Mains electricity is an alternating current, shortened to a.c., because the current keeps changing direction. Energy is transferred electrically from the power station to the home and then to whatever is plugged in.
In a heating device such as a kettle, electrical energy is transferred to the thermal store of the water. This is the useful transfer. Some energy is wasted because the kettle itself gets warm and heats the surroundings.
In a motor, such as the one in a fan or a washing machine, electrical energy is transferred to the kinetic store of the moving parts. Energy is wasted in two main ways. Friction in the bearings transfers energy to thermal energy, and the resistance of the wires heats them as current passes through. Some energy is also wasted as sound.